GitLab

* Add generic metrics for Source & Registry Errors

Change-Id: Ie145f200f815712ec372fca1c897bee3710b045b

* add label to distinguish read errors

Change-Id: I9fb1295c6fb3b2c5814ba942b4af91e1fca1c2c1

* detect write errors

Change-Id: I524360923359a5aebe6224c4e32553b138dfbdab

* revert back to label less metrics

Change-Id: Id689e0ba8c3a40a520f5af73219a4e202c167e03

* fixup Gopkg.lock

Change-Id: I3e3fdc8ad792128421b92db587bdde6e788fea58